The isothermal diffusion of Zn was described in terms of the Longini reaction and a recombination process. It was assumed that, during diffusion, highly mobile Zn interstitials recombined with a Ga vacancy and became a relatively immobile site defect. It was noted that the long-term profile of the total Zn concentration was governed mainly by the vacancy concentration profile. All of the known concentration profiles could be obtained for a constant diffusivity, without using fitting parameters. A new method was proposed for determining the diffusivities of interstitial Zn, of Zn in Ga lattice sites, and of vacancies. These coefficients were deduced from existing experimental data. It was shown that the apparent dependence of the Zn diffusivity upon its background concentration was due to its recombination with Ga vacancies.

N.N.Grigorev, T.A.Kudykina: Fizika i Tekhnika Poluprovodnikov, 1997, 31[6], 697-702 (Semiconductors, 1997, 31[6], 595-9)